Push carts used to carry heavy loads, such as industrial and medical equipment, inside buildings having corridors and hallways, must be readily and accurately steerable to avoid damage to structures or injury to personnel located within such corridors and hallways. Such carts may be integrated into the lower housings or bases of such industrial and medical equipment, so as to form a unitary structure therewith.
Medical carts, hospital beds, and other medical equipment having casters may, in the prior art, have been provided with caster control mechanisms which afforded “neutral”, “brake”, and “steer” caster functions. In a neutral mode, some such mechanisms may have precluded rotational movement of a caster about its vertical axis, whereas in a steer mode, rotational movement of the caster about its vertical axis may have been permitted and, in a brake mode, rotational movement of the caster about its horizontal axis may have been precluded. Prior art control mechanisms of this type may have included two pedals connected to each other by a pivotable shaft as in U.S. Pat. No. 5,377,372 which issued to Rudolf et al. on Jan. 3, 1995 for a “Hospital Bed Castor Control Mechanism”. The mechanism disclosed by Rudolf, however, provided links which moved (in unison) either towards, or away from, their respective ends. Accordingly, the Rudolf control mechanism either locked a caster at both ends of the bed from swivelling (in unison), or unlocked both of these casters (in unison), allowing them both to swivel. This and other prior art control mechanisms may have failed to afford any selection of caster swivelling as between the ends of the bed.
Various other control mechanisms may have been known in the prior art, including others which provided pedals with a main connecting rod between them that pivoted, or which provided a cable, an electronic controller and motor, or a solenoid for operational control of the mechanism. Other prior art may have provided for casters to be locked at one end, only, or for front and rear wheels to be interconnected only by a stabilizer bar.
What may be needed is a sturdy mechanical control device for selectively locking either (one or more) front casters, or (one or more) rear casters, while the opposite end casters remain free to rotate about a vertical axis, with such control device being readily operable by one or more users from either end, or both ends, of the cart.
There may be a need for such a control device which preferably provides the aforesaid functionality via a straight-forward substantially rigid, longitudinally sliding rod member that interconnects foot-operable pedals at the front and back ends of the cart.
Additionally, or instead, a cart may be needed which has casters—preferably four casters—mounted on a main load carrying basal body with a foot-operable mechanism at both the front and rear ends of the cart, which permits selection, from either of the aforesaid ends, of one of the following alternatives: (a) all casters being swivelable; (b) the front casters being swivelable, and one or more back casters each being locked against rotation about a respective vertical axis; or (c) the back casters being swivelable, and one or more front casters each being locked against rotation about its respective vertical axis. There may be a need for a cart which can, without requiring an operator to switch ends, enable selective movement between (a) a front-locked steering configuration, (b) a neutral intermediate unlocked steering configuration, and (c) a back-locked steering configuration. A selective control mechanism may be needed which can help make a cart readily and accurately steerable, from either end, for use in carting heavy loads in narrow corridors and otherwise.
There may also be a need for such a control mechanism which may be readily adapted for use with a cart having only three casters or more than four casters.
It is an object of the present invention to solve, obviate or mitigate one or more problems, disadvantages and/or shortcomings associated with the prior art, to meet or provide for one or more needs and/or advantages, and/or to achieve one or more objects of the invention—one or more of which may preferably be readily appreciable by and/or suggested to those skilled in the art in view of the teachings and/or disclosures hereof.